Allow each model run to have a different experiment ID

[alistairsellar]

Ultimately we will want to use CMEW to compare runs from different experiments, e.g. historical (coupled) vs amip (atmosphere-only) to understand the impact of atmosphere-ocean coupling. Each model development run (reference and control) should therefore have its own experiment id specified in the CMEW config, and passed through to both CDDS and configure_for.

Acceptance criteria

• Given multiple model runs with different experiment IDs
• When configure_recipe is run
• Then the ESMValTool recipes contain the correct experiment IDs for each model run

Details

• Complexity: low